Grocery carts and similar hand-propelled vehicles are typically supported by several wheel bracket mechanisms which each include a wheel bracket with two spaced flanges, a tubular spindle disposed between the flanges, an axle extending through the spindle and having its ends supported on the flanges, a wheel having an annular hole, and at least one plastic bushing or bearing disposed in the space between the spindle and the central hole through the wheel.
In operational use, forces frequently urge the wheel axially relative to the axle. For example, forces of this type are very common when a number of grocery carts are "nested" and then the line of nested carts is pushed around a corner, because the rear wheel bracket mechanisms of each cart are normally not pivotal about a vertical axis and thus axial forces are exerted on the rear wheels as they are dragged over the ground while the line of carts is turned. In a wheel assembly of the type to which the invention relates, axial forces of this type have a tendency to cause the bearings to shift axially within the central opening in the wheel, and even to begin to work their way axially out of the central opening.
An object of the present invention is therefore to provide a wheel assembly of the type mentioned above, in which the bearings provided between the spindle and wheel do not tend to shift axially when axial forces are exerted on the wheel during normal operational use of the wheel assembly.
A further object of the invention is to provide such a wheel assembly which is structurally simple and is inexpensive to manufacture and assemble.